Effect of age and severity of cognitive dysfunction on two simple tasks in pet dogs.

Dogs exhibit age-dependent losses in learning and memory as well as a progressive accumulation of neuropathology that parallels that observed in normal human aging and early Alzheimer's disease. These deficits have been extensively studied using a number of standard cognitive tasks in the laboratory; however, appropriate tools for their assessment in veterinary clinics are still lacking. The aim of this study was to evaluate the effect of age and the severity of cognitive dysfunction syndrome (CDS) on two simple tests conducted in a clinical setting. A food searching (FS) task and a problem-solving (PS) task were administered to young (1-4 years, n=9), middle-aged (5-8 years, n=10), cognitively unimpaired aged (≥9 years, n=31), and cognitively impaired aged (≥ 9 years, n=37) dogs. Cognitive status was classified using an owner-based questionnaire, and in the impaired group, dogs were categorized as having either mild or severe CDS. During the FS task, younger dogs (<9 years) were able to locate the food more quickly and with more success than the aged groups (≥9 years). Dogs with severe CDS exhibited poorer performance than those with mild CDS or their healthy counterparts. In the PS task, younger dogs performed better than the aged dogs in obtaining food, but there were no differences related to CDS severity. The FS task might help to better characterize cognitively affected dogs in the clinical setting than the PS task. These and similar tasks require further investigations in the field.

Effect of straw on lamb welfare, production performance and meat quality during the finishing phase of fattening.

The studies analyse the effect of straw on lamb welfare, production and meat quality in finishing lambs. Two studies were carried out. Study 1 included two treatments and two replicates with six lambs each (17.20±0.2 kg). One pen was provided with straw for forage and bedding while the other had none. Feeding with concentrate was ad libitum. Live weight and concentrate consumption were recorded and average daily gain and conversion index calculated. Stereotypes, agonistic and affiliative interactions and physiological indicators of stress were analysed. In study 2, 24 lambs were divided into two groups to analyse the effect of treatments on meat and carcass quality. No significant differences in production or meat quality traits were observed. Lambs housed without straw had higher levels of cortisol and stereotypes. Affiliative interactions were greater in lambs without straw. Results suggest that straw can be considered an effective environment-enriching tool to improve welfare.

Effect of age and severity of cognitive dysfunction on spontaneous activity in pet dogs - part 1: locomotor and exploratory behaviour.

Age-related cognitive dysfunction syndrome (CDS) has been reported in dogs and it is considered a natural model for Alzheimer's disease in humans. Changes in spontaneous activity (including locomotor and exploratory behaviour) and social responsiveness have been related to the age and cognitive status of kennel-reared Beagle dogs. The aim of this study was to assess the influence of age and severity of CDS on locomotor and exploratory behaviour of privately owned dogs. This is the first part of a two-part report on spontaneous activity in pet dogs. An open-field (OF) test and a curiosity test were administered at baseline and 6 months later to young (1-4 years, n=9), middle-aged (5-8 years, n=9), cognitively unimpaired aged (≥ 9 years, n=31), and cognitively impaired aged ( ≥ 9 years, n=36) animals. Classification of cognitive status was carried out using an owner-based observational questionnaire, and in the cognitively impaired group, the dogs were categorised as having either mild or severe cognitive impairment. Dogs were recorded during sessions in the testing room and the video-recordings were subsequently analysed. The severity of CDS (but not age) influenced locomotion and exploratory behaviour so that the more severe the impairment, the higher the locomotor activity and frequency of corner-directed (aimless) behaviours, and the lower the frequency of door-aimed activities. Curiosity directed toward novel stimuli exhibited an age-dependent decline although severely affected animals displayed more sniffing episodes directed towards the objects. OF activity did not change after 6 months. Testing aged pet dogs for spontaneous behaviour might help to better characterise cognitively affected individuals.

Effect of age and severity of cognitive dysfunction on spontaneous activity in pet dogs - part 2: social responsiveness.

Changes in social interactions with owners and other dogs are frequently observed in dogs with cognitive dysfunction syndrome (CDS). The aim of this work was to assess the effect of age and severity of CDS on social responsiveness. This is the second part of a 2-part report on spontaneous activity in pet dogs. A human interaction test and a mirror test were administered at baseline and 6 months later to assess social responses to humans and conspecifics, respectively, to four groups of privately-owned dogs: young (n=9), middle-aged (n=9), cognitively unimpaired aged (n=31), and cognitively impaired aged (n=36). The severity of cognitive impairment was considered in the last group and dogs were categorised as having either mild or severe CDS. The influence of the person and the mirror on locomotion and exploratory behaviour was also studied. Dogs were recorded in a testing room and the video recordings were subsequently analysed. Young dogs displayed more interactions involving physical contact with a person. Young and middle-aged dogs showed more vocalisations in response to social isolation. In contrast, aged animals spent more time in front of the mirror. Changes in social responsiveness associated with severe CDS included decreased response to social isolation and human interaction and increased time in front of the mirror, suggesting a deficit in habituation. Testing of spontaneous activity might help to characterise CDS in aged dogs, a condition increasingly diagnosed in veterinary clinics and a potentially useful natural model of Alzheimer's disease in humans.

Effect of fluoxetine on blood concentrations of serotonin, cortisol and dehydroepiandrosterone in canine aggression.

Canine aggression directed towards people is the most frequent reason for referral to behaviour practices. The serotonergic system and the hypothalamic-pituitary-adrenal (HPA) axis are believed to play an important role in controlling aggression. The selective serotonin reuptake inhibitor fluoxetine is the most commonly used drug in canine aggression. The aim of the present study was to assess the effect of a 30-day-long fluoxetine treatment on the peripheral serotonergic system and the HPA axis in canine aggression. To this end, the concentrations of serum serotonin (5-HT) and plasma cortisol and dehydroepiandrosterone (DHEA) were analysed in a group of aggressive (n = 22) and nonaggressive dogs (n = 9) during pre- (day 0) and posttreatment (day 30) conditions. Treatment caused a significant decrease in 5-HT concentrations (46% in the aggressive group and 32% in the control group). There was a trend towards a rise of DHEA/cortisol ratio values after treatment both in the aggressive and the control group. The determination of blood 5-HT and the DHEA/cortisol ratio could have important clinical applications in the future for deciding which animals might benefit from a given treatment as well as for monitoring the response. Further large-scale studies with this aim should be carried out to obtain sound conclusions.

Papel del eje corticotropo en la agresividad canina / No disponible

No disponible

Prevalence and risk factors of behavioural changes associated with age-related cognitive impairment in geriatric dogs.

OBJECTIVES: The aim of this study was to describe the prevalence and severity of behavioural changes associated with age and their relationship to risk factors such as sex, reproductive status, bodyweight and age. METHODS: A cross-sectional study design was chosen. A total of 325 geriatric dogs were included. Owners of dogs older than nine years were interviewed by a veterinary behaviourist. Structured phone interviews were used to gather information about four behavioural categories related to cognitive impairment: sleep/wake cycles, social interaction, learning and house training and signs of disorientation. RESULTS: Signs of cognitive impairment showed a prevalence of 22.5 per cent in geriatric dogs. Sex and age emerged as significant predictor variables. Females and neutered dogs were significantly more affected than males and entire dogs, respectively. Prevalence and severity increased with age. Although weight was not a statistically significant predictor variable, smaller animals had greater odds of showing age-related cognitive impairment. The most impaired behavioural categories were social interaction and house training. CLINICAL SIGNIFICANCE: Age-related behavioural changes should be considered by practicing veterinarians because of their relative high prevalence among geriatric dogs, especially in females.

Effect of lairage duration on rabbit welfare and meat quality.

This study determined whether short (2h) or long (8h) lairage at an abattoir had an effect on plasma stress indicators (haematocrit, glucose, lactate, creatine phosphokinase and corticosterone), instrumental meat quality (pH24, water holding capacity, colour, raw and cooked texture) and sensory meat quality (using a trained sensory panel) in rabbits. The effect of the position of the animals on a multifloor rolling cage stand during lairage was also assessed. Lairage time had a significant effect on blood stress indicators, but only a slight effect on meat quality traits. A lairage duration of 6-8h is recommended.

Journey length and high temperatures: effects on rabbit welfare and meat quality.

The transport of domestic animals by road can increase levels of stress and decrease meat quality, especially in unfavourable climates. The purpose of this study was to investigate the effect of journey duration and vertical position on the transport truck on some physiological indicators of stress and on instrumental meat quality parameters in commercial rabbits. In the summer months (June and July, 2003), 78 rabbits were subjected to either long (7 h) (LJ) or short (1 h) (SJ) journeys (3 replicates each, n = 6) between the farm and an abattoir in northern Spain. The position (top, middle, or bottom) occupied by the rabbits on the Multi-Floor cage Rolling Stand (MFRS) of the transport truck was recorded. Blood samples were collected at sticking and meat pH was measured at 24 h post-mortem (pH24). At 48 h post-mortem, samples of the M. longissimus dorsi were used to determine water-holding capacity (WHC) and instrumental tenderness using an INSTRON machine. The levels of corticosterone, glucose, lactate, and creatine kinase were slightly higher in LJ than in SJ samples, but the difference was not statistically significant (p < or = 0.10). Independent of journey length, rabbits in the middle and bottom of the MFRS showed higher levels (p < or = 0.05) of glucose and creatine kinase (middle), and corticosterone (bottom) than the rabbits located at the top floor. The pH 24 and WHC values of the SJ and LJ rabbits did not differ significantly. Journey length had a significant effect (p < or = 0.01) on meat tenderness. The meat from rabbits subjected to LJ had higher values of maximum stress and total toughness than did the SJ rabbits (p < or = 0.05). There were similar differences (p < or = 0.05) between LJ and SJ rabbits in their stress values of compression at 20% and 40% (measures of the tenderness of raw meat). In hot weather, the position on the transport truck appeared to have a greater effect on rabbit welfare than the duration of the journey.

Effect of transport stress on physiological responses of male bovines.

Forty-eight slaughter bulls were transported by road in groups of eight for approximately 30 min, 3 h and 6 h in two replicates. Animal welfare during the transport process was assessed. Loadings and unloadings were evaluated with a scoring method. Heart rates were monitored at the farm before loading and during all stages of transport. Blood samples were taken from all animals a week before transport and at sticking and analysed in terms of haematological values: hematocrit, haemoglobin, red and white blood cells (RBC and WBC), differential WBC counts and neutrophil:lymphocyte ratio. Glucose, creatine kinase, lactate and cortisol were also determined. To evaluate differences in meat quality, pH and water-holding capacity (WHC) were measured 24 h after slaughter. The loading and unloading scores were very low (low stress) but were associated with changes in heart rate, especially loading. Animals recovered their resting heart rate during the journey in medium and long transports. On the other hand, animals transported around 30 min maintained an elevated heart rate during the whole journey. All animals showed a stress response with significantly higher (p < 0.05) levels of erythrocyte series, N:L ratio, glucose and lactate. Animals transported for 3 and 6 hours had significantly (P<0.05) higher levels of cortisol than controls or 30 min transports, without differences between control and the shortest journey. Different transport times did not influence meat quality. Under good conditions, the transport had a slight effect on welfare, meat quality or physiological parameters related with stress.

Effect of commercial transport in Spain on cattle welfare and meat quality.

The purpose of this work was to determine the effect of transport of cattle from the farm to the abattoir on the animal's welfare and post mortem meat quality (instrumental and sensorial). Thirty-nine commercial journeys were followed in Spain from July 2000 to July 2001 at varying distances from a local abattoir in the city of Zaragoza. Blood samples were taken at the farm and at sticking and meat pH24 was measured at 24 hours post-mortem. Samples from the M. longissimus dorsi thoracis were taken from 48 slaughter bulls and analysed in terms of instrumental and sensorial qualities. Cortisol, glucose, CPK, lactate and N:L ratio increased during transport compared to control values. Cortisol was higher after 1-2 h transport compared to journeys that were less than 1 h or more than 2 h long. In general the parameters indicated slightly more stressful conditions under winter conditions than in the summer. Meat tenderness measured by a Warner-Bratzler device demonstrated that there was no significant effect of either transport time or season. There was no significant change in pH24 or meat colour at 24 h with transport time. Transport time had a significant effect (p < 0.05) on overall liking and animals transported in summer had slightly more tender meat and higher overall liking.

Effect of transport time on welfare and meat quality in pigs.

The purpose of this study was to determine the effects of transport duration on some welfare and meat quality parameters. For the study 144 pigs were used. One group of 72 animals was subjected to 15 min and the others to 3 h transport time. Blood from all animals was analysed in order to detect stress-susceptible pigs and assess pre-slaughter stress. Meat quality parameters were analysed from Longissimus thoracis and Semimembranosus muscles. It was concluded that under normal Spanish commercial conditions, pigs subjected to short transport showed a more intense stress response and poorer meat quality than pigs subjected to moderately long transport when they were immediately slaughtered on arrival at the slaughterhouse. Transport of 3 h might have allowed the animals to adapt to transport conditions and then could act as a resting period like a lairage time. The effect of transport time on welfare and meat quality parameters was more important than genotype and sex. Nevertheless, from the point of view of blood enzyme activities, genetically stress susceptible females transported for 3 h were more sensitive to muscle damage.

Critical points in the transport of cattle to slaughter in Spain that may compromise the animals' welfare.

The welfare of cattle depends greatly on the attitudes and training of stockpersons and on the availability of appropriate facilities. Much has been learned about stress during transport, but less attention has been paid to identifying and correcting critical points, partly because they vary widely both nationally and internationally. A survey of cattle transport in Spain was made in an effort to determine which parts of the process most compromised the animals' welfare. Data were collected on the methods and facilities for loading and unloading, transport times, types of vehicle and slaughterhouse practices. Loading facilities were adequate and loading times generally short but some farms continued to use an electric goad and weather-proofing was generally poor. The average journey time within Spain was three-and-a-half hours, but many trips were made abroad (especially to Italy), few drivers received specific training courses and the types and quality of vehicles varied widely. The average unloading time was very short but the animals were not always inspected for injuries or dirtiness. Lairage times were normally more than eight hours but few slaughterhouses had air-conditioning equipment to prevent excessive heat or dehydration. Almost all stockpersons avoided either regrouping animals or housing or transporting animals at high densities.

Differences in the biological stress responses of two cattle breeds to walking up to mountain pastures in the Pyrenees.

The aim of this experiment was to study the biological responses of Pirenaica and Parda Alpina cows (2-4 years old, n = 32) and their calves (2-4 months old, n = 32) to the physical exercise of climbing to mountain pastures in spring. These two breeds have a different sensitivity to stress-induced myopathy, the Pirenaica calves being highly sensitive. The animals walked 14 km with an elevation increase of 600 m, in approximately 3 h. Blood samples were obtained the day before, immediately after the move to the mountain pastures and the following day. The plasma cortisol levels in Pirenaica cows were significantly higher than in Parda Alpina cows under basal conditions, but disappeared in later samples. There were also significant differences in the hematological parameters. Under basal conditions, the red blood cell counts, packed cell volume, and hemoglobin content of blood were higher in Parda Alpina than in Pirenaica cows, but calves of both breeds did not differ. On the other hand, the calves of both breeds were more sensitive than their dams to the exercise, as shown by the large increase in white blood cell counts with a reversal of the lymphocytes:neutrophils ratio, a consequence of cortisol secretion. In calves the largest differences were observed in the muscle enzyme activity levels measured in serum (creatin kinase, lactic dehydrogenase, aspartate amino transferase and alanine amino transferase), which were always higher in the Pirenaica calves both under basal conditions and after exercise. These biological changes reflected the sensitivity of Pirenaica calves to muscular problems when they walk up to the pasture. It was concluded that genetic factors and age might play essential roles in the neuroendocrine and metabolic adaptation to this unusual physical exercise.

Effect of genetic factors on the criteria of stress in fighting bulls.

The effect of 40 genetic markers (blood groups and biochemical polymorphisms) on 5 haematological parameters (haematocrit, haemoglobin concentration, red blood cells count, white blood cells count and differential leucocyte count) was studied in 179 fighting bulls to investigate whether genetic background was related to stress endurance. Analysis of data was carried out by Harvey's methods (1977). Environmental factors (season, management before the bullfight, "encierro" and suffered punishment), body constitution and pedigree were also included in the analysis. The A, B and S system of cattle blood groups, erythrocyte carbonic anhydrase (Ca) and transferrin (Tf) genotypes showed a significant effect on all studied parameters. Our results show that fighting bulls with the H antigen and those without A, G2 and G3 antigens had lower haematocrit and haemoglobin concentrations than the average population, whereas the fighting bulls with CaS/CaS and TfA/TfE genotypes showed a higher reversal of the leukocyte differential count than the average population. These results may suggest a better adaptation to resistance to stress in animals displaying H antigens and CaS/CaS, TfA/TfE genotypes and in those without A, G2 and G3 antigens.

Independent segregation of a hyperactive hypothalamic-hypophyso-adrenal axis and a reduced behavioural reactivity in pigs.

When compared to European Large White, Chinese Meishan pigs have high levels of circulating ACTH and cortisol, and a reduced behavioural reactivity in various challenging situations such as exposure to a novel environment, two characteristic features of depression. We investigated whether this association is genetically built in or whether these psychobiological characteristics are fortuitously associated. Six-week-old piglets from the segregating F2 crosses between the Meishan and Large White breeds were studied in a standardised protocol of novel environment exposure. As expected from the genetic diversity, a wide range of variation was recorded for behavioural reactivity (locomotion, vocalisations). ACTH, cortisol, and glucose were measured in blood samples taken immediately before the test and at the end of the session. Again these measures varied considerably between animals, and the continuous distribution of the scores suggested that they are under control of numerous genes. Furthermore, no correlation could be found between neuroendocrine and behavioural measures. This result demonstrates that the association between high ACTH/corticosteroid levels and a low behavioural reactivity is not genetically controlled.

Facilitation and feedback in the hypothalamo-pituitary-adrenal axis during food restriction in rats.

After 4 weeks of food restriction to 50% of ad libitum intake in rats, plasma corticosterone levels were increased, without any change in adrenal weight, and with no evidence of sympathetic nervous system activation (as measured by Tyrosine Hydroxylase and Phenylethanolamine N-Methyl Transferase activities in the adrenal gland). Plasma corticosterone levels were normalized wih the addition of 35% of the calories as sugar. The adrenocortical axis activity was therefore investigated in more detail (nycthemeral cycle of corticosterone levels, ACTH and corticosterone response to a CRF challenge) in ad libitum fed rats and in animals fed 85% or 50% of the intake of the control animals, just before switching the lights off in order to maintain the diurnal rhythm of food intake. Food restriction to 85% did not change mean plasma corticosterone levels but sharpened the peak of corticosterone measured in the evening, indicating that the adrenocortical axis is more sensitive to the endogenous signals responsible for its diurnal cycle of activity. Indeed, the ACTH response to CRF was also increased. A 50% food restriction regimen increased mean corticosterone levels and attenuated the day/night difference, with high corticosterone levels maintained throughout the day. However, the ACTH response to CRF was not different from that measured in ad libitum fed rats, but the corticosterone response was lower, confirming that the adrenal gland is hyposensitive to ACTH. The results are discussed in terms of the balance between inhibiting/activating mechanisms and endocrine/neural influences at each level of the hypothalamo-hypophyso-adrenal axis, depending on the level of food deprivation.

[Relationship between genetic markers and serum enzymatic activity in fighting bulls]. / Relation entre marqueurs génétiques et activités enzymatiques sériques chez les taureaux de combat.

The relationships between 41 genetic markers (blood groups and biochemical polymorphisms), 3 environmental factors (season, management before the Lidia ("encierro"), punishment suffered), body constitution, and pedigree on the one hand, and the activity of muscular enzymes in serum, creatine kinase (CK), lactate dehydrogenase (LDH), aspartate transaminase (AST)) on the other, were analyzed in 179 fighting bulls. The C system of cattle blood groups and the "encierro" were significantly related to the activity of the muscular enzymes of the studied animals. The fighting bulls with the W1 and C1 antigens had a higher CK and LDH activity respectively, whereas the fighting bulls with the X1 antigen as well as those that participate in the "encierro" had a lower AST activity. This results could suggest a lesser degree of muscular injury during the Lidia in animals with X1 antigen, in those that participate in the "encierro", and in those without W1 and C1 antigens.

[Muscular lesions and enzymatic activities in fighting bulls]. / Lésions musculaires et activitiés enzymatiques chez les bovins de combat.

The aim of this study was to determine whether some muscular pathology existed in fighting bulls, in relation or not to the weakness shown in these animals during the bullfight (corrida for males and tienta for females). Creatinine kinase (CK), lactate dehydrogenase (LDH) and aspartate transaminase (AST) serum enzyme activities were increased after the corrida or the tienta. Most of the fighting bulls (78%) had some histological lesions in the skeletal or cardiac muscle, with predominance of chronic lesions. Clinical signs of these chronic lesions could only be seen after some trigger-effect, such as physical, exercise or stress, as shown after the corrida or tienta.